Effects of nutritional history on the subsequent and overall growth performance and carcass traits of pigs

Abstract

Sixty-four crossbred pigs were used to investigate the effects of starter (S; simple or complex), grower (G; 0.423 or 0.765 g lysine/MJ DE) and finisher (F) diets (0.423 or 0.612 g lysine/MJ DE) on the subsequent and overall growth performance and carcass traits. Average initial weights were 6.8, 22.4 and 50.5 kg for the S, G and F phases, respectively. Pigs offered the complex starter diet grew faster (P < 0.01) and more efficiently (P < 0.05) than those offered the simple starter diet. The S diet, however, had no effect on weight gain of pigs in the subsequent phases. During the G phase, pigs offered the high-amino acid diet grew faster (P = 0.09), and had lower ultrasound backfat thickness (P < 0.001) than those offered the low-amino acid diet. During the F phase, however, pigs offered the low-amino acid diet during the G phase grew faster (P < 0.05) and more efficiently (P = 0.09) than those offered the high-amino acid diet. Because of this turnaround, there was no difference in the overall performance of pigs during the G-F phase. Similarly, the G diet had no clear effects on final carcass traits or lean accretion. The results indicate that formulating diets to promote optimum performance of starter pigs can be justified. In contrast, grower pigs can be offered diets that are marginally deficient in amino acids without adversely affecting overall growth rate or final carcass traits.